<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    div {
      width: 600px;
      height: 600px;
      border: 1px solid #000;
      background: url('./images/1.jpg') no-repeat center center / 100% 100%;
      /* background-size: 100% 100%; */

      /* 
      background的连写：
        background：color image repeat position / size

        解决方法：
          1、要么把单独的样式写在连写的下面
          2、要么把单独的样式写在连写的里面
      */
    
      background: color image repeat position/size;

    }
  </style>
</head>
<body>
  <div></div>
</body>
</html>